A cadaveric study of relationships among rotational alignment reference axes of distal femur and tibial mechanical axis / 中华外科杂志

<p><b>OBJECTIVES</b>To investigate the relationships among rotational alignment reference axes of distal femur and tibial mechanical axis, and determine the safest rotational alignment reference axis.</p><p><b>METHODS</b>Digital photos were taken of 30 cadaveric lower extremities with knee in extension and flexion at 90 degrees , angles were measured among tibial mechanical axis and a line perpendicular to clinical epicondylar axis, a line perpendicular to surgical epicondylar axis, Whiteside's line and femoral mechanical axis. Statistical analysis of relationships among those axes were performed.</p><p><b>RESULTS</b>The angles among the tibial mechanical axis and a line perpendicular to the clinical epicondylar axis, a line perpendicular to the surgical epicondylar axis, Whiteside's line and femoral mechanical axis were 0.6 degrees varus, 3.9 degrees varus, 0.2 degrees valgus and 3.0 degrees varus respectively. The angle between the femoral mechanical axis and the tibial mechanical axis was significantly larger than the angles among the tibial mechanical axis and a line perpendicular to the clinical epicondylar axis, the Whiteside's line (P < 0.05). There was no significant difference compared with the angle between a line perpendicular to the surgical epicondylar axis and the tibial mechanical axis. Angles of the clinical epicondylar axis, the surgical epicondylar axis and the Whiteside's line between knee extension and flexion were 2.3 degrees valgus, 0.9 degrees varus and 3.1 degrees valgus respectively.</p><p><b>CONCLUSION</b>The surgical epicondylar axis rather than the clinical epicondylar axis or the Whiteside's line is the safest femoral rotational alignment reference axis intraoperatively.</p>

Arthroscopic simultaneous reconstruction of posterior cruciate ligament using double femoral tunnel technique and anterior cruciate ligament with achilles allograft / 中华外科杂志

<p><b>OBJECTIVES</b>To introduce the technique of arthroscopic simultaneous reconstruction of posterior cruciate ligament (PCL) using double femoral tunnel, single-bundle transtibial tunnel PCL technique and anterior cruciate ligament (ACL) with achilles allograft, and to evaluate the clinical outcome.</p><p><b>METHODS</b>Fourteen patients with PCL and ACL injuries after a minimum follow-up 18 months were received. Arthroscopically assisted simultaneous ACL/PCL reconstruction with achilles allograft were performed using the single-incision endoscopic ACL technique and the double femoral tunnel, single-bundle transtibial tunnel PCL technique. The Lysholm and Tegner knee score scale were used for functional evaluation. All patients were evaluated with physical examination and KT-1000 arthrometer testing. The mean knee flexion was (123.6 +/- 2.5) degrees preoperatively. The Lysholm score was 52.8 +/- 2.2. The Tegner score was 5.9 +/- 0.5 before injury, 1.2 +/- 0.9 preoperatively.</p><p><b>RESULTS</b>The mean time from injury to the reconstructive procedure was 19.5 d. The mean knee flexion was (117.9 +/- 2.8) degrees postoperatively( t = 1.54, P = 0.14). As to the Lachman test for 14 patients, the results of 13 patients (92.9%) was negative. As to posterior drawer test, the results of 12 patients (85.7%) was negative. The Lysholm score was 92.9 +/- 3.3 at final evaluation (t = 17.009, P < 0.001). KT-1000 arthrometer testing at 25 degrees knee flexion showed that the side-to-side difference was below 2 mm in 9 cases, 3-5 mm in 4 cases, 6 mm in 1 case. At 75 degrees knee flexion the difference was below 2 mm in 10 cases, 3-5 mm in 3 cases, 6 mm in 1 case. The Tegner score was 5.4 +/- 0.8 at final evaluation. The difference between the preoperative score and the postoperative was statistically significant (F = 4.2, P < 0.01).</p><p><b>CONCLUSIONS</b>Combined ACL and PCL injuries can be successfully treated with arthroscopic simultaneous reconstruction of PCL using double femoral tunnel technique and ACL with achilles allograft. The double femoral tunnel technique more closely approximates the anatomic insertion the native PCL. Most patients recover a functionally stable knee.</p>

Effect of increased posterior tibial slope or partial posterior cruciate ligament release on knee kinematics of total knee arthroplasty / 中华外科杂志

<p><b>OBJECTIVE</b>To compare the effects of increased posterior tibial slope or partial posterior cruciate ligament (PCL) release on knee kinematics of total knee arthroplasty (TKA).</p><p><b>METHODS</b>Anteroposterior laxity, rotational laxity, varus and valgus laxity and maximum flexion angle were evaluated in 6 normal cadaver knees and the knees after TKA at flexion 0 degrees , 30 degrees , 60 degrees , 90 degrees and 120 degrees . Then the femoral prosthesis was shifted 5 mm posteriorly to simulate the tightly implanted knee. The same tests were performed on the tightly implanted knees. After that, the posterior tibial slope was increased 4 degrees or the PCL was partially released, and the same tests were made as in the normal knees respectively. Statistical analysis of the results was made using student's t test.</p><p><b>RESULTS</b>Anteroposterior laxity, rotational laxity and varus and valgus laxity of the tightly implanted knees at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees were significantly less than those of the normal TKA knees (P < 0.05). Compared with the tightly implanted knees, anteroposterior laxity, rotational laxity and varus and valgus laxity at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees significantly improved after increased 4 degrees posterior tibial slope (P < 0.05); in the partial PCL released group, anteroposterior laxity at flexion 30 degrees , 60 degrees , 90 degrees and 120 degrees was significantly improved (P < 0.05), varus and valgus laxity was significantly improved only at flexion 90 degrees (P < 0.05), and rotational laxity was significantly improved at flexion 30 degrees , 60 degrees and 90 degrees (P < 0.05). Compared with PCL released group, varus and valgus laxity at flexion 30 degrees , 60 degrees and 90 degrees and rotational laxity at flexion 0 degrees , 30 degrees , 60 degrees and 90 degrees were significantly improved in the group of increased 4 degrees posterior tibial slope (P < 0.05). Maximum flexion angle of the tightly implanted knee (120.4 degrees ) was less than that of the normal TKA knees (130.3 degrees , P < 0.05) and that of increased 4 degrees posterior tibial slope group (131.1 degrees , P < 0.05). There was no significant difference at the maximum flexion angle between the increased 4 degrees posterior tibial slope group and the PCL released group (131.1 degrees vs 124.0 degrees , P = 0.0816).</p><p><b>CONCLUSIONS</b>Anteroposterior laxity, varus and valgus laxity, rotational laxity and maximum flexion angle of the tightly implanted knees are less than those of the normal TKA knees. After increased 4 degrees posterior tibial slope, these indexes are improved significantly. Partial PCL released can significantly improve the anteroposterior laxity and had less effect on the varus and valgus laxity, rotational laxity and maximum flexion angle. So, a knee that is tight in flexion can be more likely to be corrected by increasing posterior tibial slope than by partially releasing PCL.</p>

The incidence and variation of tunnel enlargement after anterior cruciate ligament reconstruction / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the incidence and variation of tunnel enlargement after anterior cruciate ligament (ACL) reconstruction.</p><p><b>METHODS</b>ACL reconstructions using hamstring tendons were performed in 58 patients (58 knees) in the study. MRI scans were taken in a consistent manner at 1, 3, 6, 12 and 24 months after surgery to measure tibial and femoral tunnel expansion.</p><p><b>RESULTS</b>Femoral tunnel enlargement was observed in 9 knees (9/58, 15.5%); Tibial tunnel enlargement was found in 12 knees (12/58, 20.7%). Of those with enlarged bone tunnels, there was no significant difference of tunnel diameters between 1 and 3 months after surgery (P>0.05). Six, 12 and 24 months postoperatively, the average tunnel diameters were larger than those of 1 or 3 months after surgery (P<0.05), however, no significant difference was found in between the tunnel diameters 6, 12 and 24 months postoperatively either (P>0.05).</p><p><b>CONCLUSION</b>Tunnel expansion mainly occurs during 3 to 6 months after surgery, and it remains basically unchanged between 12 and 24 months postoperatively.</p>